The subject matter of the invention is a composition for the oxidative dyeing of hair based on 5-halogen-2,4-bis(alkylamino)-1-alkylbenzenes as couplers and new 5-halogen-2,4-bis(alkylamino)-1-alkylbenzenes.
Oxidative dyes have achieved considerable importance in hair dyeing practice. The dyes are produced by oxidative coupling of developers and couplers in the hair shaft. This leads to very intensive hair colorings with very good color fastness. Moreover, different shades can be produced by combining suitable developers and couplers.
Preferably, 2,5-diaminotoluene, 1,4-diaminobenzene, 2-(2'-hydroxyethyl)-1,4-diaminobenzene, 4-aminophenol, 4-amino-2-aminomethylphenol, and 4-amino-3-methylphenol are used as developers.
Preferred couplers include m-phenylenediamine and its derivatives such as 2,4-diaminophenoxyethanol, 2,4-diaminobenzyl alcohol, 2-amino-4-(2'-hydroxyethyl)aminoanisole or pyridine derivatives such as 3,5-diamino-2,6-dimethoxypyridine as blue coupler, 1-naphthol, m-aminophenol and its derivatives such as 2-amino-4-chloro-6-methylphenol, 3-amino-2-methylphenol, 4-amino-2-hydroxyphenoxyethanol, and 3-amino-5-hydroxy-2,6-dimethoxypyridine as red couplers, as well as resorcinol, 4-chlororesorcinol, 4,6-dichlororesorcinol, 2-methylresorcinol, 4-hydroxy-1,2-methylenedioxybenzene, 4-(2'-hydroxyethyl)amino-1,2-methylenedioxybenzene, and 4-hydroxyindole as couplers for the brown-blond range.
There are numerous special requirements demanded of oxidative dyes which are used for dyeing human hair. For example, they must be unobjectionable in toxicological and dermatological respects and must enable the desired intensity of coloring. In addition, a favorable fastness to light, permanent waving, acids and rubbing are required of the achieved hair colorings. But, in every instance, such hair coloring must remain stable over a period of at least 4 to 6 weeks without being affected by light, rubbing or chemical agents. Moreover, it must be possible for a wide assortment of different shades to be produced by combining suitable developers and couplers.
However, the couplers currently used in hair dyes to achieve the red and clear blue shades in particular cannot satisfy all of the requirements specified above.
The 2,4-diamino-5-tetrafluoroethoxytoluene known from DE-OS 34 30 513 shows no mutagenicity in the Ames test, but the depth of color and light fastness of the colorings achieved with this coupler are not satisfactory.
The couplers 2,4-diamino-5-ethoxytoluene and 2,4-diamino-5-(2'-hydroxyethyl)oxytoluene described in DE-OS 36 22 784 possess good toxicological characteristics, but the coloring achieved by them with developers such as p-aminophenol or its derivatives are very washed out.